Rainbow Electronics ATA6624 - Manual (Page 7)

7
4986F–AUTO–07/08
ATA6622/ATA6624/ATA6626
4. Modes of Operation
Figure 4-1. Modes of Operation
4.1 Normal Mode
This is the normal transmitting and receiving mode. The voltage regulator is in Normal Mode and
can source 50 mA. The undervoltage detection is activated. The watchdog needs a trigger sig-
nal from NTRIG to avoid resets at NRES. If NRES is switched to low, the IC changes state to
Fail-safe Mode.
4.2 Silent Mode
A falling edge at EN when TXD is high switches the IC into Silent Mode. The TXD Signal has to
be logic high during the Mode Select window (see
Figure 4-2 on page 8 ). The transmission path
is disabled in Silent Mode. The overall supply current from V
Batt
is a combination of the I
VSsi
57 µA plus the VCC regulator output current I
VCC
.
The 3.3V/5V regulator with a 2% tolerance can source up to 50 mA. The internal slave termina-
tion between the LIN pin and the VS pin is disabled in Silent Mode to minimize the power
dissipation in the event that the LIN pin is short-circuited to GND. Only a weak pull-up current
(typically 10 µA) between the LIN pin and the VS pin is present. Silent Mode can be activated
independently from the actual level on the LIN, WAKE, or KL_15 pins. If an undervoltage condi-
tion occurs, the NRES is switched to low, and the IC changes its state to Fail-safe Mode.
Unpowered Mode
V
Batt
= 0V
a: V
S
> 5V
b: V
S
< 4V
c: Bus wake-up event
d: Wake up from WAKE or KL_15 pin
Fail-safe Mode
Normal Mode
VCC: 3.3V/5V/50 mA
with undervoltage
monitoring
Communication: ON
Watchdog: ON
VCC: 3.3V/5V/50 mA
with undervoltage monitoring
Communication: OFF
Watchdog: ON
Silent Mode
VCC: 3.3V/5V/50 mA
with undervoltage monitoring
Communication: OFF
Watchdog: OFF
Sleep Mode
VCC: switched off
Communication: OFF
Watchdog: OFF
Go to silent command
a
TXD = 0
EN = 0
TXD = 1
EN = 0
EN = 1
EN = 1
EN = 1
b
b
b
c + d + e
e
c + d
b
Local wake-up event
Go to sleep command
e: NRES switches to low